<button class="layui-btn" onclick="setTop();">${tagBody}</button>

<script>

    function setTop(){
        //多窗口模式，层叠置顶
        layer.open({
            type: 2 //此处以iframe举例
            , title: '${tagBody}'
            , area: ['${width}', '${height}']
            , shade: 0
            , maxmin: false

            , content: '${url}'
            , btn: ['朕知道了'] //只是为了演示
            , yes: function () {
                layer.closeAll();
            }
            , zIndex: layer.zIndex //重点1
            , success: function (layero) {
                layer.setTop(layero); //重点2
            }
        });
    }

</script>